gruppo

This assumes you're using worthy components (Yeah I'm an elitist), so note that most of the cable/housing brands come in varying degrees of quality. For instance the Yokozuna stuff can be had in standard grade, still pretty good, and in Reaction grade, much better. The same goes for the Jagwire & Shimano bulk and kits cables/housing (Though most of the SRAM seems pretty good). So be careful when buying whatever, stay away from house-brand stuff, and ask for lined, lubed, non-compressable housing in either 4mm or 5mm diameters, depending on the use; and stainless, drawn, small diameter cables with the correct ends for your application - and in my 30 year's experience installing/servicing thousands of upper- to high-end brake/derailleur systems, there's no performance advantage with teflon coated cables, and I've installed lots of them (There, I've said it). And it's usually better to measure what you need and ask for individual cables, lengths of housing, and endcaps/crimps, rather than kits (Tell them you want the stuff the guys in back use to set up their Red, Super Record, and Dura Ace shifters/brakes).

The reason I'm rambling on about all this is because of the huge numbers of service problems I see in my shop that are simply the result of poor quality cables/housing/endcaps, their lousey installation, and poorly maintained and dirty components.